GNSS Receiver Phase Clock Accuracy During Signal Degradation
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Solution Overview
Problem
Current GNSS receivers lack a method to maintain and restore phase clock accuracy without external assistance, especially when signal degradation occurs due to environmental changes or jamming, leading to impaired output performance across various industries.
Innovation Solution
The system maintains a phase history of the GNSS receiver output by classifying time intervals and visible satellites, allowing for the calculation of a stable phase clock output even during signal degradation, using historical data to adjust and regenerate the phase clock, and enhances clock performance under variable conditions like temperature changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If Phase Lock Loops use history of frequency clock to maintain frequency holdover quality, then frequency clock stability is improved, but phase clock accuracy deteriorates during signal loss
Solution Approach 1:
The system performs preliminary actions by maintaining a history of phase measurements during periods when GNSS signals are available. This historical phase data is stored and prepared in advance, so that when signal loss occurs, the pre-collected phase history can be immediately used to restore phase accuracy without waiting for signal recovery
Solution Approach 2:
The invention introduces an intermediary mechanism - a phase history buffer or memory - that stores past phase measurements. This intermediary allows the system to bridge the gap between frequency holdover (which maintains stability) and phase accuracy recovery (which requires precise phase information), by using the stored phase history as a mediator to reconstruct accurate phase clocks during signal degradation
2Measurement precision
If external clock sources or atomic clocks are used to maintain phase clock accuracy, then phase clock performance is improved, but system cost increases
Solution Approach 1:
The system implements self-service by using its own internal phase history data to maintain and restore phase clock accuracy during signal degradation. Instead of relying on external atomic clocks or expensive reference sources, the GNSS receiver uses its own previously collected phase measurements to correct and maintain its output, making the system self-sufficient during impairments
Solution Approach 2:
The invention changes the operational parameters by switching from real-time phase measurement to historical phase data retrieval during signal loss. By changing the time parameter (using past data instead of current data) and the source parameter (internal history instead of external reference), the system maintains phase accuracy without requiring expensive external clock sources
Data Source
AI summary
Systems and methods of storing phase history, and enhancing and restoring phase accuracy for a embedded Global Navigation Satellite System (GNSS) receiver include storing a phase history of the GNSS receiver output; determining an expected value of phase of the GNSS receiver output based on the phase history; and, responsive to a degradation of the GNSS receiver output, adjusting the GNSS receiver output utilizing the expected value of phase. The systems and method can further include, responsive to degradation being a loss of the GNSS receiver output, utilizing a holdover output from a physical frequency reference and with a phase adjusted based on the expected value of phase, and, responsive to the variation, utilizing the phase history to re-generate the GNSS receiver output for performance enhancement.